Melanoma is a cancer resulting from the abnormal proliferation and spread (metastasis) of pigment cells (melanocytes) in the skin. The disease is related, to a certain extent, to exposure to UV radiation, e.g., sunlight. In the U.S. about 2% of all cancer deaths (about 10,000/yr.) may be attributed to melanomas. In the past twenty years the frequency of deaths attributed to melanomas has about doubled.
The usual treatment for melanoma is a complete surgical excision of the melanoma before the onset of metastasis. Once metastasis has occurred there is no cure and the disease is considered terminal.
It has been shown that in humans the cells that synthesize melanin, such as melanoma cells, selectively take up and use 3-(3,4-dihydroxy)phenyl-L-alanine (L-DOPA) as a substrate which is converted in the presence of specialized enzyme systems into melanin.
It is well known that inorganic phosphate is necessary for the synthesis of DNA and is essential for cell division. When .sup.32 P is incorporated into the DNA of dividing cells it destroys them by causing scission in the DNA. Polycythemia, a disorder involving abnormal division of the red blood cells, can be cured by administration, to the patient, of .sup.32 P. However, the dosages of .sup.32 P required for the destruction of most cancerous cells is high and causes undesirable side effects.
In accordance with the invention there is provided a composition for treatment of melanomas without the aforementioned concommitant deleterious effects.